The heated seats in newer automobiles produce heat via a coiled wire. As power travels through the coil, its winding design resists the electricity and therefore generates friction and heat. Heated seats can malfunction for a number of reasons. Whether the defect lies in the fuse, the electrical connections or the heating coil, having a thorough troubleshooting protocol will enable you to determine the problem with your heated seats quickly every time.
Locate the fuse box in your vehicle, and check the fuse for the heated seats to see whether or not it is broken. If it is broken, remove it and install a new fuse.
Start your vehicle, and then flip the relay switch for the heated seats on. Most vehicles feature a “heated seat” light on the dash that comes on when you turn the relay switch on. If this light fails to come on, there is a problem with the relay switch. Unscrew the dash using a Phillips screwdriver, and then touch one of the voltmeter probes to any of the wires connected to the relay switch. Touch the other probe to the relay switch grounding wire and read the meter. Any wires that fail to register any electrical current at all will need to be replaced.
Turn the relay switch on, and then test the electrical circuit that feeds the heated seat. Place one probe on the power lead that connects to the heated seat connection and the other probe on any metal part of the seat. If the meter does not register any current, the power circuit will need to be replaced.
Pull off the electrical connection for the heated seat by hand. Test each of the three pins in the connector by placing on voltmeter probe on a pin and the other probe on any metal part of the seat. If any pin fails to register current, the connector any need to be replaced. If the pins are covered with dirt and debris, clean them off with a rag. This may be enough to fix the problem.
Place one probe on the power lead that is fed by the heated seat connection and the other probe on any metal part of the seat. If the meter does not register any current, the circuit that is fed by the heated seat connection will need to be replaced.
Unbolt the seat from the vehicle using a ratchet and socket, then unplug the two electrical connections that are attached to the seat. Pull the seat out of the vehicle and remove the circular “hog rings,” which connect the seat cover to the seat, with pliers. Pull the seat cover off and look for burn marks. If every other test has been positive, the heating coil needs to be replaced.